Rudder and stabilizer attachment for outboard motors



D. F, LINSLEY Nov. 15, 1966 RUDDER AND STABILIZER ATTACHMENT FOR OUTBOARD MOTORS Filed April 6, 1965 INVENTOR.

DUUBLAE FT LIN5LEY ATTURNEY United States Patent 3,285,219 RUDDER AND STABILIZER ATTACHMENT FOR OUTBOARD MOTORS Douglas F. Linsley, P.O. Box 324, Westport, Conn. Filed Apr. 6, 1965, Ser. No. 445,886 4 Claims. (Cl. 115-18) The present invention relates to a rudder and stabilizer attachment for outboard motors, and has for its object to provide an attachment of this character of simple, inexpensive and rugged construction which may be readily attached to a conventional outboard motor without material alteration therein, the mounting of the attachment upon the motor being simply accomplished by drilling several holes therein to receive attaching bolts.

Outboard motors are mounted upon the stern of a boat for pivotal movement about a vertical axis to accomplish steering of the boat by changing the angle of the propeller axis relatively to the boat axis, the only built-in rudder surfaces being relatively small areas of the sides of the lower part of the housing for the propeller shaft and gearing, this part of the housing usually having a cross-sectional shape which is streamlined in the direction of the propeller axis. Such rudder surfaces are forwardly of the propeller and provide very little inde pendent rudder effect, so that steering of the boat is adversely affected under wind, wave and tide conditions, particularly when the propeller is in neutral or being driven at relatively slow speed.

It is a further object of the invention to provide a rudder and stabilizer attachment in which a relatively large surfaced thin blade-like rudder means is fixedly positioned rearwardly of the propeller in a central vertical plane parallel to and coinciding with the propeller axis, thus providing a relationship wherein the propeller and rudder means do not tend to fight each other as is the case with a rudder means which has its plane of action movable relatively to the axis of the propeller. The present arrangement is such that the propeller and the plane of the rudder means always point in the same direction, thus making for less turbulance between the propeller and the rudder and enabling increased banking and faster turns especially at high speeds. In addition to increased control and safety under high speed conditions, the arrangement enables better maneuverability under low speed conditions or with the propeller in neutral, thus making for more positive maintenance of steerageway in maneuvering between boats and in docking or mooring.

Additionally, the provision of relatively large rudder surfaces in centralized fixed relation to the propeller axis gives to the operator of the boat a positive sense or feel of steering response as between the steering wheel and the rudder which is absent with the conventional outboard motor. This steering feel is important in that it gives an instinctive assurance of the direction in which the boat is moving and thus makes for more positive control and quicker sensitivity and reaction to changing conditions or hazards.

Other objects and advantages will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawings wherein a satisfactory embodiment of the invention is shown. However, it will be understood that the invention is not limited to the details disclosed but includes all such variations and modifiications as fall within the spirit of the invention and the scope of the appended claims.

In the drawings:

FIG. 1 is a side elevation of a rudder and stabilizer attachment according to the invention;

FIG. 2 is a rearward end elevation;

Patented Nov. 15, 1966 "ice FIG. 3 is a top plan view;

FIG. 4 is a fragmentary vertical sectional view on an enlarged scale taken along the line 44 of FIG. 1;

FIG. 5 is a horizontal sectional view on an enlarged scale taken along the line 55 of FIG. 1;

FIG. 6 is a fragmentary side elevation on a reduced scale showing the attachment assembled with an outboard motor, only, the lower propeller mounting portion of the latter being illustrated;

FIG. 7 is a rearward end elevation of the assembly as seen in FIG. 6;

FIG. 8 is a sectional top plan view taken along the line 8--8 of FIG. 6; and

FIG. 9 is a fragmentary vertical sectional view similar to FIG. 4 and showing a modification of the means for assembling the parts of the attachment.

Referring to the drawing and more particularly to FIGS. 1-4, the rudder and stabilizer attachment according to the exemplary embodiment of the invention illustrated therein comprises a horizontal top plate part 10 adapted, as will presently more fully appear, to mount the attachment on the outboard motor and provide auxiliary stabilizing surfaces therefor, this plate part being provided centrally in its forward portion with a forwardly divergent slot 11 opening to the forward end of the plate, the forward edges 12-12 at each side of the slot being preferably inclined rearwardly and outwardly and beveled forwardly between the upper and lower surfaces to minimize resistance to the flow of water in the assembled relation with the motor. The outer ends of the forward edges are convexly rounded where they connect with the forward parallel side edges 1313, the rearward side edges 1414 being disposed at equal rearwardly convergent angles and being joined at their rearward ends with a tail edge 15 of generally V-shape in plan and of V-shape in cross-section to minimize rearward edge turbulence.

The rudder part 16 is in the form of a relatively large surfaced thin plate having a right angularly bent,,flange 17 at its upper edge which is engaged with the under side of the rearward portion of the plate part 10 where it is secured by a series of bolt, lock-washer and nut assemblies 18 engaged in registering holes 19 and 20 in the plate part and the flange. The rudder part is so positioned that its central vertical plane coincides with the longitudinal center line of the plate part 10. Its forward edge 21 is preferably disposed at a rearwardly and downwardly inclined angle and is of V-shape in cross section, its rearward edge 22 is inclined downwardly and rearwardly at a somewhat greater angle than that of the edge 21 and its lower edge 23 is inclined upwardly and rearwardly. This angularity of the edges of the rudder part minimizes drag and turbulence.

At the opposite side of the rudder part from the flange 17 there is provided a reinforcing bracket part 24 secured to the rudder part by bolt, lock-washer and nut assemblies 25 engaged through registering holes 26 and 27 in the rudder and bracket parts. The upper end of the reinforcing bracket part is provided with a right angularly bent flange 28 extending in opposite direction from the flange 17 of the rudder part and is secured to the under side of the top plate part 10 by bolt, lock-Washer and nut assemblies 29 engaged in registering holes 30 and 31 in the top plate part and flange. The side edges 32 and 33 of the bracket part converge downwardly to a rounded lower edge 34 and these edges are beveled outwardly from the outer to the inner surfaces of the bracket to minimize turbulence.

The top plate, rudder and bracket parts are preferably formed of flat sheets or plates of a suitable rigid material capable of withstanding immersion without corrosion, such material being for example an aluminum alloy sheet of suitable thickness and strength. The bolt, lockwasher and nut assemblies are preferably formed of stainless steel. The assembly of the three sheet metal parts of the attachment by means of removable bolts permits of the convenient substantially flat packaging of the attachment in knockdown form ready for easy assembly by the user simply by securing the parts together by means of the bolts. If desired, however, the parts may be permanently assembled, for example by means of the rivets 35 as seen in FIG. 9.

The outboard motor of conventional type includes a vertically disposed housing 36 having a pair of horizontal stabilizer fins 37-37 extending laterally at each side and disposed above the propeller 38, the latter having its horizontal shaft mounted in an extension 39 of the housing which terminates in a foot or skeg 40 for the purpose of protecting the propeller against contact with a bottom surface. The rearward part of the housing 36 is also provided with a downwardly projecting exhaust pipe 41v disposed forwardly of the propeller. The top plate part of the attachment is engaged upon the upper surface of the fins 37 with the rearward exhaust pipe portion of the housing disposed within the opening 11, Where it is secured by bolt, lock-washer and nut assemblies 42 engaged in holes 43 in the plate part and holes 44 drilled in the fins in registering relation with the holes 43.

In the assembled relation the rudder part 16 is dis posed in a vertical plane parallel to and coinciding with the horizontal axis of the propeller so that it is centralized with respect to the propeller stream and, by virtue of its relative thinness, permits balanced passage of the stream at each side without turbulence and without any appreciable drag. At the same time the relatively Wide side surfaces of the rudder part provide for effectual steering through turning of the outboard motor about its ver tical pivot axis. Additionally, the top plate part 10 constitutes an extension of the stabilizer fins 37 and thus, at the same time the large area rudder surfaces provide horizontal stabilization, provides for increased vertical stabilization under adverse wind, wave and tide conditions.

What is claimed is:

1. A rudder and stabilizer device for attachment to an outboard motor provided with a central housing, a pair of stabilizing fins extending laterally at each side of said housing, a housing extension extending below said housing, and a propeller carried by said housing extension below said stabilizer fins having its axis of rotation substantially horizontal and coinciding in parallel relation with the central longitudinal vertical plane of said motor; said device comprising a horizontal top plate part of symmetrical outline at each side of its longitudinal center line and having forward and rearward co-planar portions, said forward portion having a central longitudinal slot opening to its forward edge whereby said forward portion is adapted to engage the upper sides of said fins at each side of said housing with said housing disposed within said slot and with the longitudinal center line of said slot coinciding in parallel relation with said central longitudinal vertical plane of said motor, means carried by said forward portion for effecting attachment to said fins, a rudder part in the form of a relatively thin vertical plate secured to the underside of said rearward portion of said top plate and disposed edgewise. with its central vertical plane in parallel aligned relation with said longitudinal center line of said slot whereby in the attached relation of the device said vertical plate is in centralized parallel relation with said propeller axis with its forward edge in rearwardly opposed relation to said propeller, and whereby the propeller slip-stream is substantially equally divided by said vertical plate and exerts substantially equally balanced pressures upon the side surfaces of said vertical plate and upon the under surface of said top plate at each side of said vertical plate.

2. The invention is defined in claim 1, wherein said rudder part has a downwardly and rearwardly inclined forward edge, a downwardly and rearwardly inclined rearward edge, and an upwardly and rearwardly inclined lower edge.

3. The invention as defined in claim 2, wherein the rearward inclination of said rearward edge is greater than that of said forward edge.

4. The invention as defined in claim 2, wherein said forward and rearward edges are of V-shape in crosssection.

References Cited by the Examiner UNITED STATES PATENTS 2,654,336 10/1954 Katzung et al. -18 2,956,533 10/1960 De Yo 115l8 MILTON BUCHLER, Primary Examiner. ANDREW H. FARRELL, Examiner. 

1. A RUDDER AND STABILIZER DEVICE FOR ATTACHMENT TO AN OUTBOARD MOTOR PROVIDED WITH A CENTRAL HOUSING, A PAIR OF STABILIZING FINS EXTENDING LATERALLY AT EACH SIDE OF SAID HOUSING, A HOUSING EXTENSION EXTENDING BELOW SAID HOUSING, AND A PROPELLER CARRIED BY SAID HOUSING EXTENSION BELOW SAID STABILIZER FINS HAVING ITS AXIS FOR ROTATION SUBSTANTIALLY HORIZONTAL AND COINCIDING IN PARALLEL RELATION WITH THE CENTRAL LONGITUDINAL VERTICAL PLACNE OF SAID MOTOR; SAID DEVICE COMPRISING A HORIZONTAL TOP PLATE PART OF SYMMETRICAL OUTLINE AT EACH SIDE OF ITS LONGITUDINAL CENTER LINE AND HAVING FORWARD AND REARWARD CO-PLANAR PORTIONS, SAID FORWARD PORTION HAVING A CENTRAL LONGITUDINAL SLOT OPENING TO ITS FORWARD EDGE WHEREBY SADI FORWARD PORTION IS ADAPTED TO ENGAGE THE UPPER SIDES OF SAID FINS AT EACH SIDE OF SAID HOUSING WITH SAID HOUSING DISPOSED WITHIN SAID SLOT AND WITH THE LONGITUDINAL CENTER LINE OF SAID SLOT COINCIDING IN PARALLEL RELATION WITH SAID CENTRAL LONGITUDINAL VERTICAL PLANE OF SAID MOTOR, MEANS CARRIED BY SAID FORWARD PORTION FOR EFFECTING ATTACHMENT TO SAID FINS, A RUDDER PART IN THE FORM OF A RELATIVELY THIN VERTICAL PLATE SECURED TO THE UNDERSIDE OF SAID REARWARD PORTION OF SAID TOP PLATE AND DISPOSED EDGEWIDE WITH ITS CENTRAL VERTICAL PLANE IN PARALLEL ALIGNED RELATION WITH SAID LONGITUDINAL CENTER LINE OF SAID SLOT WHEREBY IN THE ATTACHED RELATION OF THE DEVICE SAID VERTICAL PLATE IS IN CENTRALIZED PARALLEL RELTION WITH SAID PROPELLER AXIS WITH ITS FORWARD EDGE IN REARWARDLY OPPOSED RELATION TO SID PROPELLER, AND WHEREBY THE PROPELLER SLIP-STREAM IS SUBSTANTIALLY EQUALLY DIVIDED BY SAID VERTICAL PLANE AND EXERTS SUBSTANTIALLY EQUALLY BALANCED PRESSURES UPON THE SIDE SURFACES OF SAID VERTICAL PLATE AND UPON THE UNDER SURFACE OF SAID TOP PLATE AT EACH SIDE OF SAID VERTICAL PLATE. 